2014HS: 31004 Computational Photography

But if vertical slope indicates objects at infinity, is the statement on slide 27 "Point towards infinity: slope becomes horizontal" wrong? 

What I don't get is, a point infinetely far away, would produces rays that arrive parallel to each other when they "hit" the v-plane. 

And also, what does "Origin of v relative to t coordinate of each ray" (slide 26) mean? The origin of v is where the ray hits the t-axis.. where is the origin of the t-axis?